1. Field of the Invention
The present invention relates to a side airbag system for vehicles, and more particularly to a side airbag system, which has an integrated tether, and manufacturing and folding methods of the side airbag system, by which a passenger""s head and thorax can be safely protected, and manufacturing cost and labor can be reduced.
2. Discussion of the Related Art
In general, passengers, including drivers, who utilize an automobile of a grand and high-quality style, pay much attention to not only the performance of the automobile, but also the safety system for protecting the passengers from injury in the event of an accident. Such safety systems include a safety belt, an airbag system, a steering safety-shaft, etc., which are designed to protect the passengers as best as possible by automatically operating in the event of an accident.
Especially, the airbag system instantly injects an exploding gas into an airbag cushion when the automobile experiences a collision or a rapid decrease of speed. Then, the rapidly expanding airbag cushion surrounds the front or the side of a passenger, so as to prevent the passenger from coming into collision with hard objects such as a front glass or a steering wheel of an automobile.
Several airbag systems functioning as above have been disclosed by U.S. Pat. Nos. 5,938,232, 5,860,673, 5,586,782, and 5,547,214, all of which disclose side airbag systems for protecting the drivers and the passengers from the lateral collision of the automobile.
FIG. 1 shows a construction of a conventional side airbag system, which includes a side impact airbag module 10 disposed at a frame 4 of a front seat 1.
The front seat 1 generally includes a seat back 2 and a seat cushion 3. The seat back 2 has a plurality of seams 6a, 6b, and 6c. The seat back 2 also has at least a wing 7 sewed at a part of the seat back 2 by the seams 6a, 6b, and 6c and extending forward therefrom.
FIG. 2 is a sectional view taken along line Cxe2x80x94C of FIG. 1, which shows that the side impact airbag module 10 includes an airbag cushion 15 and an inflator 11.
The side impact airbag module 10 is disposed in an inner space of a foam layer 5 which is surrounded by front and rear panels 2a and 2b of the seat back 2 and front and rear panels 7a and 7b of the wing 7.
The inflator 11 has an inflator housing 14 and is fixed to the frame 4 by a bolt and a nut. The frame 4 is a pipe extending in an axial direction of the seat back 2. A first safety beam 4a extending forward of the wing 7 is fixed to the frame 4, and is firmly assembled with a second safety beam 4b. Further, the bolt penetrates through the inflator housing 14 and the first safety beam 4a to be firmly tightened by the nut, so as to firmly fix the inflator 11 to the first safety beam 4a. 
The airbag cushion 15 is assembled with the inflator 11 while being folded in a compacted way. The airbag cushion 15 is inflated by a gas generated by the inflator 11 when the car comes into lateral collision. While the airbag cushion 15 is being inflated, the airbag cushion 15 breaks through the seams 6a, 6b, and 6c of the wing 7 to protrude forward from a lateral side of the seat back 2, thereby protecting a passenger""s or a driver""s thorax and head.
As shown in FIG. 3, the airbag cushion 15 is made by seaming a plurality of strips or panels 30b to 30f of a conventional flexible material. When the airbag cushion 15 has been inflated, it has a shape of a cylinder, nearly like a rectangular box.
The airbag cushion 15 is divided into a plurality of compartments 40b to 40f to form a plurality of chambers 50b to 50f, so as to minimize the loss of pressure in the airbag cushion 15 and at the same time maintain the inflated shape of the airbag cushion 15 as best as possible when the passenger""s thorax and head collide with the airbag cushion 15. Since the chambers 50b to 50f of the airbag cushion 15 are respectively filled with the gas injected from the inflator 11, the airbag cushion 15 is shaped like a plurality of airbag cushions partitioned one from another. The construction of the airbag cushion 15 as described above is intended to overcome a difficulty of the general airbag cushion stitching process in that the panels 30b to 30f must be stitched, manually turned inside out, and then stitched again by means of a sewing machine or a like machine of fabrication equipment.
However, in the conventional side airbag system, the side impact airbag module requires a firm fixing construction between the inflator and the frame. This is because the airbag cushion, compactedly folded, violently shakes while inflating due to the high gas pressure.
Moreover, in the conventional side airbag system, although the partitioned airbag is stitched in a flat plane, both ends of a panel, a middle portion of another panel, or a predetermined portion of a panel must be individually stitched, in order to ensure that the portion functioning as a tether is formed in the airbag cushion. Therefore, in the conventional side airbag system, the efficiency is relatively low in stitching the airbag cushion, and this low efficiency increases the manufacturing cost.
Also, in the conventional side airbag system, the airbag cushion is in contact with the inflator in the state of being folded and stored. Therefore, the gas of high temperature directly comes into contact with the airbag cushion to generate thermal deformation of the airbag cushion when the gas is injected from the inflator. In order to secure a structural safety from such a thermal deformation, the airbag cushion employs panels which are relatively thick and coated overall. These coated thick panels also increase the manufacturing cost.
In addition, since the conventional airbag cushion is folded simply like an accordion, it is not competent in smoothly and uniformly dispersing the gas of high temperature and high pressure into each chamber in an initial stage of operation. Furthermore, in the conventional airbag cushion, it is difficult to control the distribution of pressure in the different chambers, when the passengers come into contact with the airbag cushion.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and it is an object of the present invention to provide a side airbag system, which has an airbag cushion stitched in a flat plane, so as to protect a passenger by preventing an initial loss of gas pressure in an inflator depending on the portion of the passenger coming into contact with the airbag cushion.
It is another object of the present invention to provide a method for manufacturing a side airbag system, by which panels can be stitched in a flat plane to easily form an integrated tether, thereby making it easy to manufacture the side airbag system, and reducing the manufacturing cost.
It is another object of the present invention to provide a method for folding a side airbag system, by which the airbag cushion can be folded corresponding to the introducing direction of the gas of high temperature and high pressure and stored in the airbag housing, so as to maximize the operation efficiency of the airbag system.
In accordance with one aspect, the present invention provides a side airbag system for protecting a passenger of an automobile from injury in the event of a lateral collision to the automobile, the side airbag system comprising:
a frame of a seat of the automobile, the frame having a fixing plate;
an airbag cushion including a first panel, a pair of second panels, and pairs of reinforcement panels, the first panel having a tether at which a plurality of vents are formed, the second panels being seamed with the first panel along first seams of the first panel, each pair of the reinforcement panels being stacked onto and seamed with each of the second panels along second seams of the second panels, the airbag cushion having an upper chamber and a lower chamber partitioned by the tether; and
an inflator assembly installed in the airbag cushion, the inflator assembly including an inflator, a mounting ring, and a mounting bracket, the mounting ring being made by winding a metal strip having a predetermined width and overlapping ends of the metal strip, the inflator being inserted through the mounting ring and then assembled with the mounting bracket, the inflator assembly having assembling bolts inserted through bolt holes of the lower chamber and being assembled to the fixing plate of the frame,
wherein the tether constantly maintains a pressure in and a shape of the airbag cushion so that a gas injected by the inflator is filled in the lower chamber prior to the upper chamber.
In accordance with another aspect, the present invention provides a method for manufacturing a side airbag system for protecting a passenger of an automobile from injury in the event of a lateral collision to the automobile, the method comprising the steps of:
stacking a first panel, a pair of second panels, and pairs of reinforcement panels in sequence;
coinciding side ends of the panels one from another and symmetrically arranging the second panels and the reinforcement panels;
stitching the first and the second panels along a first seam on the first panel;
stitching the second panels and the reinforcement panels stacked together along second seams on the second panels;
folding the first panel upward and folding the second panels and the reinforcement panels downward; and
stitching the first panel, the second panels and the reinforcement panels together along third seams at a periphery of the side airbag system.
In accordance with another aspect, the present invention provides a method for folding a side airbag system for protecting a passenger of an automobile from injury in the event of a lateral collision to the automobile, the method comprising the steps of:
folding a first panel, a pair of second panels, and pairs of reinforcement panels at a right angle with reference to first and second folding lines, and folding the panels in an opposite direction;
forming a folded body having a section of a shape including horizontally continuous S letters by repeating the previous folding step;
folding an upper body of the folded body toward a lower body of the folded body to be overlapped with each other;
bending upward the upper body and the lower body overlapped together; and
surrounding the bent folded body with a cover.